Objective To investigate the dates of 477 Chinese prenatal screening centers for previous half year analyse prena-tal screening status and provide recommendations for quality control.Methods All China prenatal screening centers were sent the data via the National Quality Assessment Scheme.This covered the software used,the risk cut-offs,monthly sample throughput,monthly median MoM of AFP,hCG,β-HCG,freeβ-HCG and uE3,monthly screening positive rate for trisomy 21,trisomy 18 and Open Neural Tube Defect.Results Screening protocol were versatile,with 73.48% (133/181)used two-marker model,24.31% (44/181)used three-marker model and 2.21% used four-marker model.About the software used, 350 laboratories never updated the screening parameters,89 laboratories had updated their median or parameter by manufac-turers,24 laboratories had updated the parameters by themselves.Cut-offs differed between laboratories.59.91% (275/459) used 1/270 as their cutoffs for trisomy 21.66.22% (296/447)used 1/350 as their cutoff for trisomy 18 and 96.52% (361/374)used cutoffs between 2.0~2.5 MOM for ONTD.Results of monthly median MOM:the percentage of laboratories that all six monthly median MOM within the target of 0.90~1.10 was 46.69% (155/332)for AFP,20.0% (4/20)for hCG, 29.17% (28/96)forβ-HCG,15.66% (31/198)for freeβ-HCG and 4.82% (11/228)for uE3.The percentage of laborato-ries that all six monthly median MOM within the target of 0.95~1.05 was 14.16% (47/332)for AFP,0% (0/20)for hCG,4.17% (4/96)forβ-HCG,12.63% (25/198)for freeβ-HCG and 4.82% (11/228)for uE3.About screening positive rate,there were difference of trisomy 2 1 positive rate in the same laboratory within the six month.Conclusion There were variations types of screening protocol,different kinds of soft platform,randomness of choice or update of medians or other important parameters and great difference in awareness of quality control.It would be taken effective and practical quality control measures to help laboratories improve quality control.

Objective To investigate the current application status of reference intervals in routine chemistry and compare with the current health industry standards .Methods By using web-based external quality assessmentsoftware system , data were collectedfrom the laboratories which attended 2012 national reference intervals investigation , including the sources of reference intervals , upper and lower limits , subgroups and grouping rules , test methods, instruments and reagents , etc.Microsoft Excell2007 and SPSS 13.0 were used to analyze the trimmed data .Results There were 385 laboratories submitting the reference intervals they had been using .Only a few of laboratories'reference intervalsweregrouped .There are some differences in grouping rulescompared with the currentstandards .Even though some of the laboratories adopt the grouping rules as the same as the standards , there are still significantstatistical differences in reference intervals between the laboratories and the health industry standards (P <0.01).Conclusions The reference intervals of routine chemistry items suggested by the health industry standards have quite big differences from thoseused in current clinical laboratories dailywork ,that might be related from the population they served and many internal influence factors. If the health industry standards are used , the evaluation and validation of reference intervals should be done first.

Objective To discuss the application of allowable total error (Tea) and allowable imprecision derived from biological variation in routine chemistry external quality assessment ( EQA) and internal quality control (IQC) and set up quality specifications of routine chemistry in our country.Methods Data of test items including K,Na,CI,Ca,P,Glu,Urea,UA,Cre,Alb,TP,TC,TG,AST,ALT,Tbil,ALP,AMY,CK,LDH,Fe,Mg,Cu,Zn and GGT was collected and evaluated by a nationwide EQA.At the same time the coefficients of variation (CVs) of these test items during the month were acquired from the IQC reports of each laboratory and then the results were analyzed.Results Percent of pass was different in these test items based on Tea derived from biological variation in EQA results.Except for items of CI,Mg,Cu and Zn,about 80％ of participant laboratories could achieve the minimum performance of biological variation.About 80％ of participant laboratories could achieve the desired performance of biological variation for K,P,Glu,Urea,UA,Cre,TC,TG,ALT,AST,Tbil,AMY,CK,LDH,Fe and GGT.About 80％ of participant laboratories could achieve the optimum performance of biological variation for Urea,UA,TC,TG,ALT,AST,Tbil,C K,and GGT.And the IQC results showed that acceptable percents of different items based on three allowable imprecision were different.More than 80％ of participant laboratories could achieve the minimum allowable imprecision for K,P,Glu,Urea,UA,TC,TG,ALT,AST,Tbil,AMY,CK,LDH,Dbil,Fe,GGT,the desirable imprecision for P,Urea,UA,TG,ALT,AST,Tbil,CK,Dbil,Fe,GGT and the optimum imprecision for TG,ALT,CK,Dbil,Fe.Conclusions The quality specifications derived from biological variation can be as evaluation criteria for EQA and IQC in order to know the detection ability of each laboratory more completely and objectively,set up quality specifications derived from allowable total error and allowable imprecision in routine chemistry and to provide basis for mutual recognition of routine chemistry test results.

Objective To summarize and analyze the results of national external quality assessment (EQA) of maternal serum prenatal screening in second trimester during 2004-2013,in order to provide a assistance for the quality improvement of the prenatal screening testing.Methods Five different concentration samples were distributed to each participated laboratories and were measured at each external quality assessment program during 2004 to 2013.The results reported in a specified time.The testing performance of alpha fetoprotein (AFP),total human chorionic gonadotropin (HCG),total β-human chorionic gonadotropin (β-HCG),free β-human chorionic gonadotropin (free β-HCG),unconjugated estriol (uE3) were evaluated.Results During 2004-2013,the number of laboratory participated increased from 57 to 500.The robust variation coefficient increased from 2.77％ to 18.98％ for AFP,5.6％ to 36.12％ for HCG,4.69％ to 24.38％ for β-HCG,2.66％ to 81.54％ for free β-HCG,and 3.83％ to 26.51％ for uE3.The percentage of passing rate reached 93％ (463/496) for AFP,66％ (35/53)for HCG,85％ (137/ 161) for β-HCG.The percentage of passing of free β-HCG (μg/L) increased from 52 ％ (24/46) to 94％ (248/264),but the passing percentage of free β-HCG (mIU/ml) were 47％ (18/38).The percentage of passing of uE3 reached 84％ (252/299).Conclusions The testing performance of AFP is best in prenatal screening,followed by β-HCG,other item testing have some problems.It is great important to improve the quality of maternal serum prenatal screening by strengthening external quality assessment and building comprehensive quality control system in China.

Objective To describe the reference intervals and their sources of tumor markers in clinical laboratories all over China.And make a comparison of difference between different testing systems.Methods The questionnaires about reference intervals of tumor markers testing were distributed to participants.The information was collected by external quality assessment software system based on website, which including upper and lower limits, sources, validation information and testing systems.The analytes were AFP, CEA, total-PSA, CA125, CA153, CA199, ferritin and free-PSA. The participants were classified according to the testing systems they used.The mean, median, maximum and minimum of each group were calculated using Microsoft Excel 2007.The difference of reference intervals between different testing systems were compared by Kruskal-Wallis test.Results The main source of reference intervals was instructions of testing system manufactures ( 83.1% for mean of 8 ratios ) .The next in sequence were instructions of reagent manufactures(8.4% for mean), National Guide to Clinical Laboratory Procedures (4.6%for mean), determined by their own laboratory(2.0% for mean) and the rest (1.9% for mean). There were 48.0% ( 1 906/3 967 ) of analytes whose reference intervals had been validated.Difference of reference intervals which was with P value of Kruskal-Wallis test with <0.05 was found between different testing system groups except the upper limit of free prostate specific antigen ( PSA ) .Conclusions Most clinical laboratories establish the reference intervals of tumor markers on the basis of instructions of testing system manufactures.The reference intervals among different testing systems have statistically significance.

Objective To compare the current application status of reference intervals in dry chemistry to the reference inter-vals of anlytes of wet chemistry in the same hospital.Methods By using web-based external quality assessment (EQA) software system,collecting the submitted data from the laboratories which attended national reference intervals investigation of reference intervals of analytes in dry chemistry and wet chemistry,using professional statistical software for analyzing the data,including paired-samples t test and Yates’Chi-square test.Results 231 laboratories submitted their investigation re-sults including the reference intervals of 23 analytes of dry and wet chemistry.69.6% (32/46)of reference intervals of ana-lytes in dry chemistry have significant statistical differences compared with the wet chemistry in paired-samples t tests. 80.4% (37/46)of medians of reference intervals of analytes in dry chemistry had significant statistical differences in loca-tions and distributions compared with medians of reference intervals of wet chemistry in the same institute.Conclusion The reference intervals of analytes of dry chemistry have differences compared with the wet chemistry in the same hospital.The medians of reference interval’s lower and higher limits of dry and wet chemistry have difference in locations and distribu-tions.Proposed to create our own reference intervals of dry chemistry in China.

Objective To evaluate hemoglobin A2 and F (HbA2 and HbF)assays in part of Thalassemia screening laborato-ries in China.Methods Two lots of controls were sent to 50 Thalassemia screening laboratories.Test results of HbA2 and HbF were collected,analyzed and evaluated by different method groups.Results 49 of all laboratories reported the results and the rate of return was 98%.The proportion of laboratories reporting acceptable results for HbA2 and HbF testing was 42.9~92.3% and 27.3% ~ 84.6% respectively.HbA2 test results from 3 laboratories for Lot 201311 and 4 for 201312 were unsatisfactory.And HbF test results from 5 laboratories for Lot 201311 and 3 for 201312 were unsatisfactory.Conclu-sion Conclude that quality in the measurement of HbA2 and HbF should be improved.

Objective To investigate the current application status of reference intervals in routine chemistry and compare with the current health industry standards draft for approval.Methods By using web-based external quality assessment (EQA)software system,collected the submitted data from the laboratories which attended national reference intervals inves-tigation,used professional statistical software to analyze the data.Results 385 laboratories had submitted the investigation results.The vast majority of the analytes of attended laboratories had significant statistical differences in comparison with the health industry standards draft for approval in no grouping and not filled groups[t = - 55.435 ~ 17.070,P < 0.05, 86.1% (31/36)].Only a few of laboratories’reference interval had been grouped (approximately 20%).There were some differences in grouping rules between laboratories and standards.Even though some of the laboratories adopt the grouping rules as same as the standards,there were still big differences in reference intervals between the laboratories and the stand-ards[t=-39.365~13.155,P <0.01,62.5% (10/16)].Conclusion The reference intervals of routine chemistry analytes suggested by the health industry standards draft for approval had quite big differences from the reference intervals used in current clinical laboratories daily work.It is important to propel the authority health industry standards to use in the daily work of clinical laboratories.The evaluation and validation of using them should be done first.

Objective To carry out the current status of internal quality control by statistical analysis of the Internal Quality Control (IQC)data of homocysteine in 2014 March.Methods Web-based External Quality Assessment (EQA)system was used to collect IQC data of homocysteine from 292 EQA participant laboratories nationwide.The data include thecoefficient of variation (CV)of IQC data under control in March 2014 and long-term cumulative data.Acceptable rates of CVs of two-lot internal quality controls in homocysteine were calculated according to 5 criteria,that were 1/3TEa,1/4TEa and the speci-fications based on biological variation including the minimal,appropriate and optimal allowable imprecision.The instrument the participant laboratories used were sorted into 6 groups and the passing rate of each group were calculated by the 5 crite-ria.Results 292 laboratories reported the data of level 1 IQC for homocysteine,106 of which reported the data of level 2 IQC.The passing rate was different according to different criteria.The passing rate had few difference by the criteria of 1/3TEa and the minimal allowable imprecision based on biological variation,which were from 63.36% to 76.42%.It was also true for 1/4TEa and the appropriate allowable imprecision based on biological variation,which were from 34.25% to 57.55. The passing rate was only 10.62%~16.98% by the criteria of appropriate allowable imprecision based on biological varia-tion.Statistical results showed that instruments the participant mainly used were HITACHI (77/292),Olympus (61/292), Roche (19/292),Beckman (14/292),Abbott (10/292)and Simens (10/292).The passing rates of all the instrument group had few difference except Simens group.Conclusion Most of the laboratories could meet the criteria of 1/3TEa and the min-imal allowable imprecision based on biological variation.But less than half of the laboratories could meet the criteria of 1/4TEa and the appropriate and optimal allowable imprecision based on biological variation.The precision performance of ho-mocysteine among laboratories needs further improvement.

The aims of this article is to provide the quality control requirements of preanalytical variation for the determination of trace element aluminum,arsenic,chromium,cadmium and mercury in samples of human origin,reduce the influence of preanalytical variation on the test results.Refer to the Clinical and Laboratory Standards Institute (CLSI) documents,Control of Preanalytical Variation in Trace Element Determinations and other references and guidelines,the methods of quality control of aluminum,arsenic,chromium,cadmium and mercury determination have been made,including:the factors needed to be considered in collection,preservation,transportation and other preanalytical factors,the abilities and considerations of laboratory staff,etc.Hope this article provide some useful suggestions and help to the laboratories of determination of aluminum,arsenic,chromium,cadmium and mercury in samples of human origin.